For efficient utilization of the very high capital investment involved in large, modern-high speed printing presses, it is virtually essential that the press delivery system, i.e., the folder, be capable of handling products of various sizes, both as to sheet size and the number of sheets that make up the end product. One aspect of the assembly of the final product from the printed web involves the ability of the folder to deliver successive intermediate products to the jaw cylinder directly, which is referred to as "straight delivery", or to collect two or even three intermediate products and deliver the collected products to the jaw cylinder, which is usually referred to as "two collect" or "three collect". Occasionally, it may be desirable for the folder to straight deliver one intermediate product and collect two other intermediate products, an operation usually termed partial collect.
Folder collect cylinders that are designed to provide either straight or collect delivery have been proposed before. For example, the folders of U.S. Pat. No. 2,797,084 issued June 25, 1957 and U.S. Pat. No. 3,865,361 issued Feb. 11, 1975, include collect cylinders having two running cam surfaces, each of which has a different profile. The follower for each pin mechanism can be adjusted to follow one or the other of the two cam surfaces, one of which provides straight delivery and the other of which provides collect delivery. Although the systems described in those patents are workable and not unduly difficult to produce and operate, they are inherently limited to either straight operation or two collect operation. Neither system provides three collect or partial collect.
U.S. Pat. No. 4,094,499 issued June 13, 1978, describes and illustrates a collect cylinder that can be adjusted for straight operation or collect operation. The gripper mechanism is controlled by a stationary cam that is profiled to open the gripper and accept a product at a taking station and to open and release the product at a delivery station but otherwise maintains the gripper closed. A rotatable running cam is mounted eccentrically, relative to the axis of the cylinder and to the axis of the stationary cam, and has camming surfaces that selectively mask the release profile of the stationary cam, thereby preventing the gripper from opening and releasing the sheet or sheets constituting the intermediate product. Because of the eccentricity of the running cam, it is said that the opening and closing of the gripper at the taking station may occur over a comparatively long time, inasmuch as the masking cam cannot in any event mask the taking profile of the stationary cam. The collect cylinder described in U.S. Pat. No. 4,094,499 appears to be capable of being designed to afford considerable versitility as to the number of intermediate products collected. On the other hand, manufacturing difficulties are inherent in making the eccentric mounting for the rotary cam and in the special machining of the masking surfaces of the rotary cam. Because the center of rotation of the rotary cam is eccentric, with respect to axis of the stationary cam, the masking surfaces of the rotary cam should not be arcuate with respect to the center of rotation but instead should be specially profiled to insure against movement of the grippers when they are silenced.